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Hello and welcome to the screencast demo lesson
The purpose of this lesson is to showcase the use of screencapturing within a tutoring lesson
The content found within this presentation has not been reviewed and should not be used for academic purposes.
Within this lesson we will look at the decimals system as well as adding and subtracting numbers with decimals
The decimal system pretty much represents different values of numbers. If we look at the example number 654 321.12345
we notice that each number can be divided into their own units or values.
Therefore, if we look at the number 2.
The number 2 represents tens. Within this value we have two tens
We now know that this two represents twenty.
The same can be done with any number
The three for example falls under the hundreds place value, therefore we know this 3 actually represents 300
This aids us when reading numbers out loud or when using numbers in any mathematical equation.
The same thing can be applied to numbers that fall to the right of the decimal point.
We should note that numbers to the left equate to whole numbers while numbers that fall to the right of the decimal point equate to fractions of numbers.
Therefore, the one here represents tenths the two hundredths, the 3 thousandths, 4 ten-thousandths and 5 hundred-thousandths.
Using this logic we can now add and subtract decimals.
If we look at these four numbers the first thing we will need to do is line up the decimal points.
Writing out the number simply as it is each decimal point will fall in a different position. Therefore we want to make sure that their all lined up.
So when we rewrite this
We want to make sure that regardless of how many numbers fall to the right and left of the decimal point, that the decimal point actually does line up.
This might be confusing for some people. One tip that is often done, is the use of zeros as placeholders.
Therefore, we know that this number is empty, but if we wanted to make sure that everything lines up, we would include zeros.
The same thing applies to subtracting numbers with decimals. What we would like to do first is make sure that each decimal point lines up.
Once this is done, we will be able to add and subtract numbers with decimals as we would with whole numbers.